The actor also plays in rock band Tenacious D, for which he has developed a set of elaborate stage moves, which combine his musical prowess with martial arts.

He said: ''I have a mini tiger roll. I learned that move back in my judo class days. It's a dive then you go into a spinning somersault. There was a time when I felt that the show wasn't complete without a mini tiger roll. It's pretty powerful.''

Jack, 42, admits the move is quite tricky to execute and he has suffered injury as a result.

He added: ''There may have been a shoulder snap. To this day I require occasional chiropractic adjustments.''

Jack has previously said he would like to do more of his own stunts in his films, particularly if he ever gets to reprise his role of Jeff 'Fats' Portnoy in 'Tropic Thunder', who can fart on command.

He said: ''I didn't do any of my own stunts in the fart department, it was all with the help of computers. They don't have the technology to place the microphones in the inner canal of my inner cavity. Someday soon I hope they'll have the science and it will catch up to my flatulent talent.''